Lamb waves offer a promising method of evaluating damage in composite materials. The Lamb wave velocity is directly related to the material parameters, so an effective tool exists to monitor damage in composites by measuring the velocity of these waves. The Lamb Wave Imager™ (LWI) uses a pulse/receive technique that excites an antisymmetric Lamb mode and measures the time-of-flight over a wide frequency range. Given the material density and plate thickness, the bending and out-of-plane shear stiffnesses are calculated from a reconstruction of the dispersion curve. In this study, the time-of-flight as well as the elastic stiffnesses D11,D22,A44, and A55 for composite samples which have undergone combined thermal and mechanical aging are obtained. The samples examined include a baseline specimen with 0 cycles, specimens which have been aged 2350 and 3530 cycles at high strain levels, and one specimen aged 3530 cycles at low strain levels.

1.
E.
Baer
,
A.
Hiltner
, and
R. J.
Morgan
, “
Biological and synthetic hierarchical composites
,”
Phys. Today
45
,
60
67
(
1992
).
2.
M. D.
Seale
,
B. T.
Smith
, and
W. H.
Prosser
, “
Lamb wave assessment of fatigue and thermal damage in composites
,”
J. Acoust. Soc. Am.
103
,
2416
2424
(
1998
).
3.
V. Dayal and V. K. Kinra, “Ultrasonic NDE of composites for transverse cracking,” in Optical Methods in Composites; Proceedings of the SEM Fall Conference on Experimental Mechanics (A88-13876 03-24) (Society for Experimental Mechanics, Inc., Bethel, CT, 1986), pp. 17–22.
4.
B.
Tang
and
E. G.
Henneke
II
, “
Lamb-wave monitoring of axial stiffness reduction of laminated composite plates
,”
Mater. Eval.
47
,
928
934
(
1989
).
5.
V. Dayal, V. Iyer, and V. K. Kinra, “Ultrasonic evaluation of microcracks in composites,” in Advances in Fracture Research; Proceedings of the Seventh International Conference on Fracture (ICF7), Vol. 5 (A90-41276 18-39) (Pergamon, New York, 1989), pp. 3291–3300.
6.
M. R.
Karim
,
A. K.
Mal
, and
Y.
Bar-Cohen
, “
Inversion of leaky Lamb wave data by simplex algorithm
,”
J. Acoust. Soc. Am.
88
,
482
491
(
1990
).
7.
A. K. Mal, M. R. Gorman, and W. H. Prosser, “Material characterization of composite laminates using low-frequency plate wave dispersion data,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 11, edited by D. O. Thompson and D. E. Chimenti (Plenum, New York, 1992), pp. 1451–1458.
8.
J.-H.
Shih
,
A. K.
Mal
, and
M.
Vemuri
, “
Plate wave characterization of stiffness degradation in composites during fatigue
,”
Res. Nondestruct. Eval.
10
,
147
162
(
1998
).
9.
K. J. Sun, “Application of guided acoustic waves to delamination detection,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 11, edited by D. O. Thompson and D. E. Chimenti (Plenum, New York, 1992), pp. 1213–1219.
10.
N.
Guo
and
P.
Cawley
, “
The interaction of Lamb waves with delaminations in composite laminates
,”
J. Acoust. Soc. Am.
94
,
2240
2246
(
1993
).
11.
N. Guo and P. Cawley, “Lamb waves for the NDE of composite laminates,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 11, edited by D. O. Thompson and D. E. Chimenti (Plenum, New York, 1992), pp. 1443–1450.
12.
Y. Bar-Cohen and D. E. Chimenti, “NDE of defects in composites using leaky Lamb waves,” in Symposium on Nondestructive Evaluation, 15th Proceedings (A86-47129 22-38) (Nondestructive Testing Information Analysis Center, San Antonio, TX, 1986), pp. 202–208.
13.
K. Balasubramaniam and J. L. Rose, “Guided plate wave potential for damage analysis of composite materials,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 9, edited by D. O. Thompson and D. E. Chimenti (Plenum, New York, 1990), pp. 1505–1512.
14.
Y. Bar-Cohen, S-S. Lih, A. Mal, and Z. Chang, “Rapid characterization of the degradation of composites using plate wave dispersion data,” in Review of Progress in Quantitative Nondestructive Evaluation, Vol. 17, edited by D. O. Thompson and D. E. Chimenti (Plenum, New York, 1998), pp. 1171–1176.
15.
W. Huang, S. M. Ziola, J. F. Dorighi, and M. R. Gorman, “Stiffness measurement and defect detection in laminated composites by dry-coupled plate waves,” in Process Control and Sensors for Manufacturing, edited by R. H. Bossi and D. M. Pepper (SPIE, Bellingham, WA, 1998), pp. 66–76.
16.
A. K. Noor and S. L. Venneri, senior editors, “New and Projected Aeronautical and Space Systems, Design Concepts, and Loads,” in Flight-Vehicle Materials, Structures, and Dynamics—Assessment and Future Directions, Vol. 1 (The American Society of Mechanical Engineers, New York, 1994), pp. 15–84.
17.
Sir Graham Sutton, Mastery of the Air (Basic Books, Inc., New York, 1965), pp. 157–166.
18.
N. F. Harpur, “Concorde structural development,” in AIAA Commercial Aircraft Design and Operation Meeting (American Institute of Aeronautics and Astronautics, New York, 1967), No. 67-402, pp. 1–14.
19.
B. Tang, E. G. Henneke II, and R. C. Stiffler, “Low frequency flexural wave propagation in laminated composite plates,” in Acousto-Ultrasonics Theory and Application, edited by John C. Duke, Jr. (Plenum, New York, 1987), pp. 45–65.
20.
B. Z. Jang, Advanced Polymer Composites (ASM International, Materials Park, OH, 1994), p. 93.
21.
I. M. Daniel and O. Ishai, Engineering Mechanics of Composite Materials (Oxford University Press, New York, 1994), pp. 34–47.
22.
W. H. Prosser, “The propagation characteristics of the plate modes of acoustic emission waves in thin aluminum plates and thin graphite/epoxy composite plates and tubes,” NASA Technical Memorandum 104187, November 1991.
This content is only available via PDF.
You do not currently have access to this content.